#302 The stringparser doesn't work as expected

[Erik Hänel]

The following operations with the string parser fail:

• logical operations together with strlen()
• storing more than one result into a data object
• recursive expressions like stringvar += replaceall(somestring)

Analysis:
The reasons are as follows:

• The logical parser doesn't understand something like true && 0
• index+1 instead of index+i is used at the relevant location in the code
• The relevant part of the code doesn't check for string vector variables used internally

Implementation:
The fixes were implemented as proposed by the analysis. Implementation tests were passed successfully.

Documentation:
The fix was noted in the changes log.

Tests:
The fixes were added to the automatic tests. No deviations detected. Bug fix implemented successfully.